Back to EveryPatent.com
United States Patent |
5,062,615
|
Schaberg
,   et al.
|
November 5, 1991
|
Apparatus for the introduction of reagents in powder form into a melting
pan
Abstract
The invention relates to apparatus for the introduction of reagents in
powder form into a melting pan, in which the lance is arranged
eccentrically with respect to the pan axis and the outlet nozzles are
directed into the larger region of the pan enclosing the pan axis. Such
apparatus is distinguished by optimum mixing in of the added reagents.
Inventors:
|
Schaberg; Frank (Oelde, DE);
Martens; Heribert (Oelde, DE);
Pohlmann; Peter (Munster, DE)
|
Assignee:
|
Krupp Polysius AG (DE)
|
Appl. No.:
|
584365 |
Filed:
|
September 17, 1990 |
Foreign Application Priority Data
Current U.S. Class: |
266/217; 266/225 |
Intern'l Class: |
C21C 005/32 |
Field of Search: |
266/216,218,225,217
|
References Cited
U.S. Patent Documents
3145245 | Aug., 1964 | Chedaille | 266/225.
|
3545960 | Dec., 1970 | McClellan et al. | 266/216.
|
3627294 | Dec., 1971 | Hill | 266/225.
|
Primary Examiner: Kastler; S.
Attorney, Agent or Firm: Learman & McCulloch
Parent Case Text
This is a continuation of copending application Ser. No. 07/345,442 filed
on May 1, 1989 now abandoned.
Claims
What is claimed is:
1. Apparatus for the introduction of powdered reagents into a melting pan
containing a melt and having a cylindrical base and a vertical center
axis, said melt having its surface at a predetermined level above the base
of said pan, said apparatus comprising a source of gas and powdered
reagent, a lance projecting downwardly into said pan with its lower end
portion forming a delivery outlet at a level between the surface of said
melt and said base, and means communicating with said lance and said
source for pneumatically supplying a gas and a powdered reagent to said
lance for discharge through the delivery outlet of said lance into said
melt, said lance being offset eccentrically of said axis of said pan, said
delivery outlet of said lance comprising a pair of circumferentially
spaced outlet nozzles at said lower end portion, each of said nozzles
being directed wholly radially outwardly of said lance below the surface
of said melt, one of said nozzles opening in a direction to one side of
said axis and the other of said nozzles opening in a direction to the
opposite side of said axis, said nozzles being spaced from one another at
an angle in the range of 60.degree. to 120.degree., said angle having its
bisector intersecting said axis.
2. The apparatus of claim 1 wherein said nozzles are offset from one
another at an angle in the range of 80.degree. to 100.degree..
3. The apparatus of claim 1 wherein said lance is offset from said vertical
pan axis a distance in the range of 0.2 to 0.8 times the radius of the
base of said pan.
4. The apparatus of claim 1 wherein said lance is offset from said vertical
pan axis a distance in the range of 0.4 to 0.6 times the radius of the
base of said pan.
Description
The invention relates to improvements in apparatus for the pneumatic
introduction of reagents in powder form into a melting pan.
BACKGROUND OF THE INVENTION
In the treatment of melts with injected reagents in powder form, for
example in the desulphurisation of crude iron or the treatment of steel,
optimum introduction of the reagents is necessary in order to achieve the
best possible utilisation of the reagents so as to reduce the process
costs as much as possible.
In the past reagents were introduced by means of a vertical lance arranged
centrally with respect to the pan axis, the reagents either being
introduced downwards through a vertical nozzle orifice or through one or
more nozzle orifices evenly distributed around the periphery of the lance.
The object of the invention is to construct apparatus in such a way that
the introduction of the reagents in powder form into the melting pan is
improved so as to produce a particularly favourable intermixing.
SUMMARY OF THE INVENTION
According to the invention the lance is arranged eccentrically with respect
to the pan axis, and the outlet nozzle or nozzles are directed into the
larger region of the pan which faces away from the peripheral wall of the
pan near the lance and encloses the pan axis.
Using such a solution the melt intermixing time is substantially reduced by
comparison with known constructions because the progress of the
intermixing is more favourable as a result of the altered flow profile.
A reduction of the specific quantities added is also achieved by the
increased accuracy provided by the apparatus according to the invention.
THE DRAWINGS
The invention will be explained in greater detail below with the aid of the
drawings, in which:
FIGS. 1 and 2 show a section and a plan view of known apparatus.
FIGS. 3 and 4 show a section and a plan view of apparatus according to the
invention.
FIGS. 5 and 6 show a section and a plan view of the apparatus according to
the invention (rotated by 90.degree. with respect to the views in FIGS. 3
and 4).
DETAILED DESCRIPTION
FIGS. 1 and 2 show the known prior art which forms the starting point for
the invention. A lance 2, which is arranged vertically and centrally with
respect to the axis of the melting pan 1 and is provided at its lower end
with a downwardly-directed nozzle orifice 2a and a plurality of horizontal
nozzle orifices, e.g. 2b, 2c, evenly distributed about the periphery,
serves for the introduction of reagents in powder form into a melting pan
1.
The hatched area 3 in FIG. 2 extends approximately uniformly about the
lance 2 and is a so called "scavenging spot", i.e. a region in which the
reagents blown out of the nozzle orifices enter the melt 4.
The reagents in powder form which are blown in pneumatically are moved
upwards in the melt 4 by the carrier air, producing a division of the flow
at the level marked by the broken line 5, as indicated schematically by
the curve 6. In the central region the flow is directed upwards, whilst in
a comparatively wide annular edge zone it is directed downwards.
By contrast, FIGS. 3 to 6 show the apparatus according to the invention.
The lance 12 is arranged eccentrically with respect to the axis 10 of the
melting pan 11, as much as 0.2 to 0.8 times the pan radius R preferably
offset with respect to the pan axis 10 by 0.4 to 0.6 times the pan radius
R (measured on the base of the pan).
In the illustrated embodiment the lance 12 is provided at its lower end
with two outlet nozzles 12a, 12b which are offset with respect to one
another by an angle of between 60.degree. and 120.degree., preferably by
an angle between 80.degree. and 100.degree., with the angle bisector 20
intersecting the pan axis 10.
As FIG. 4 shows, the two outlet nozzles 12a, 12b are aligned in the larger
region of the pan 11 which faces away from the peripheral wall of the pan
11 near the lance 11 and encloses the pan axis, so that an elongated
scavenging spot characterised by the area 13 is produced with its narrow
extent reaching for the lance 12 to approximately over the axis 10 and its
elongated extent running at right angles thereto.
If one considers the flow at the level of the line 15, the relationships
characterised by the curve 16 are established. A further characteristic of
this is the dip in the curve 16 which can be seen in the view according to
FIG. 5 which is rotated by 90.degree.. Generally speaking, it can be
established that in the construction according to the invention the
reagents in powder form which are blown in are distributed better and more
rapidly in the melt 14 and localised overconcentrations are avoided.
Top